This invention is concerned with inspection apparatus for inspecting articles moving on a conveyor, the apparatus comprising scanning means operable to scan each article from two directions, which are substantially perpendicular to one another, as the article moves on the conveyor and to produce two output signals each of which is respectively proportional to the apparent amount by which the article leans from the vertical in the scanning direction, processing means operative to square the two output signals and to add the squares together thereby producing a lean signal indicating the true amount of lean from the vertical of the article, comparing means operative to compare the lean signal with a preselected standard and to provide a reject signal in the event that the lean signal exceeds the preselected standard, and rejecting means downstream of the scanning means operative on receipt of a reject signal from the comparing means to remove the article from the conveyor.
Glass containers which have just been manufactured are conventionally placed on a conveyor which carries them to inspection apparatus which inspects the containers to determine whether they are fit for their intended purpose. Such inspection apparatus may comprise, for example, lean detecting means for detecting whether the containers lean from the vertical by more than an acceptable amount, optical means for examining the containers optically, means for checking the neck opening size, and means for checking the containers for leaks. Such lean detecting means conventionally comprises scanning means operable to scan each container from two directions which are mutually perpendicular to one another as the container moves on the conveyor. From the output signals of the scanning means, processing means calculates a signal indicating the lean of the container, comparing means compares this signal with a standard preselected to indicate the maximum acceptable amount of lean, and rejecting means removes the container from the conveyor before it reaches the remainder of the inspecting apparatus if the standard is exceeded. Such scanning means and associated equipment is described in U.S. Pat. No. 3,754,123. The lean detecting means including the reject means is located upstream of the remainder of the inspecting apparatus so that the leaning containers cannot damage the remainder of the inspecting apparatus or jam it. The containers not rejected by the lean detecting means are brought to rest at various stations for inspection to take place. Second reject means is associated with the remainder of the inspecting apparatus and removes any containers which fail tests at the stations.
Inspection apparatus as mentioned above may comprise reading means for reading markings on the container which indicate in which mould the container was made since the output from many moulds is normally fed to the same inspection apparatus. In this case, it is possible to detect when containers from a particular mould fail particular tests and to take remedial action by changing the mould or moulding conditions. However, it is not possible to detect whether containers rejected by the lean detecting means would have failed any of the remaining tests. Furthermore, since the reading means is normally associated with the optical means and, therefore, is located downstream of the lean detecting means, the moulds in which the containers rejected by the lean detecting means were made are not recorded.
It is an object of the present invention to provide inspection apparatus in which increased information about leaning articles can be recorded.